US20120235255A1 - MEMS acoustic pressure sensor device and method for making same - Google Patents
MEMS acoustic pressure sensor device and method for making same Download PDFInfo
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- US20120235255A1 US20120235255A1 US13/068,554 US201113068554A US2012235255A1 US 20120235255 A1 US20120235255 A1 US 20120235255A1 US 201113068554 A US201113068554 A US 201113068554A US 2012235255 A1 US2012235255 A1 US 2012235255A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
- G01L9/0073—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance using a semiconductive diaphragm
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- the present invention relates to a Micro-Electro-Mechanical System (MEMS) acoustic pressure sensor device and its manufacturing method, in particular to such device that includes a multilayer structure having multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered, and a method for making such device.
- MEMS Micro-Electro-Mechanical System
- FIG. 1 shows a multilayer MEMS structure disclosed in U.S. Pat. No. 7,202,101.
- the multilayer MEMS structure 10 is formed on a substrate 11 and it includes: a sacrificial layer 12 formed on the substrate 11 ; a fixed electrode 13 ; a sacrificial layer 14 ; a first metal layer 15 formed on the sacrificial layer 14 ; a sacrificial layer 16 ; a second metal layer 17 formed on the sacrificial layer 16 ; a sacrificial layer 18 ; and a flexible or movable diaphragm 19 formed by sealing each metal layer with a polymer film.
- the first metal layer 15 is a mesh-shaped metal layer to improve the properties of the MEMS acoustic pressure sensor device, wherein the mesh metal layer allows etching vapor to pass through the metal layers so that the etching vapor can react with and remove the desired portions of the sacrificial layers 12 , 14 , 16 and 18 .
- the mesh metal layer 15 also alleviates the stress issue of the multilayer MEMS structure.
- this mesh metal layer decreases the sensitivity of acoustic pressure and restricts the applications of the MEMS device.
- a part of the sacrificial layers 12 , 14 , 16 and 18 is removed, and a polymer material is deposited around each mesh metal layer for sealing each mesh metal layer so that the sensitivity can be enhanced thereby.
- this polymer deposition process is not commonly available in a CMOS manufacturing fab, and it is difficult to integrate the polymer deposition process with the current CMOS manufacturing process.
- the present invention proposes a multilayer structure with staggered metal layers and its manufacturing method.
- An objective of the present invention is to provide a MEMS acoustic pressure sensor device.
- Another objective of the present invention is to provide a method for manufacturing a MEMS acoustic pressure sensor device.
- a MEMS acoustic pressure sensor device comprising: a substrate; a fixed electrode provided on the substrate; and a multilayer structure including: multiple metal layers; and multiple metal plugs connecting the multiple metal layers; wherein a cavity is formed between the multilayer structure and the fixed electrode, and each metal layer in the multilayer structure includes multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave.
- a method for manufacturing a MEMS acoustic pressure sensor device comprising: providing a substrate; forming a fixed electrode on the substrate; forming at least one sacrificial layer; forming multiple metal layers on the sacrificial layer, the multiple metal layers having multiple metal sections, respectively; and forming multiple metal plugs for connecting the multiple metal layers to form a multilayer structure, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave; and removing the sacrificial layer to form a cavity.
- the foregoing MEMS acoustic pressure sensor device preferably further comprises a supporting structure fixed on the substrate and connected with the multilayer structure for supporting the multilayer structure.
- the foregoing MEMS acoustic pressure sensor device preferably further comprises an insulating layer connected between the supporting structure and the substrate.
- each multiple metal layer preferably overlaps a portion of at least another metal layer from top view.
- the multilayer structure preferably includes at least one opening at a lateral side of the multilayer structure.
- the substrate preferably includes at least one vent.
- each metal layer preferably includes at least one material of gold, silver, titanium, tantalum, copper, aluminum, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
- each metal plug preferably includes at least one material of tungsten, gold, silver, titanium, tantalum, copper, aluminum, tungsten carbide, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, tungsten oxide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, tungsten nitride, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
- FIG. 1 shows a multilayer MEMS structure disclosed in U.S. Pat. No. 7,202,101.
- FIGS. 2A-2J illustrate, by cross-section view, a manufacturing process according to a first embodiment of the present invention.
- FIG. 3 shows a second embodiment of the present invention.
- FIG. 4 shows a third embodiment of the present invention.
- FIGS. 5A-5J show a fourth embodiment of the present invention.
- FIGS. 6A-6D show a fifth embodiment of the present invention.
- FIGS. 7A-7F show a sixth embodiment of the present invention.
- FIGS. 2A-2J illustrate, by cross-section view, a manufacturing process according to a first embodiment of the present invention.
- a substrate 22 is provided, and the substrate 22 may be, for example but not limited to, a silicon substrate.
- a sacrificial layer 24 is formed on the substrate 22 , which may include, for example but not limited to, a dielectric material of silicon dioxide, fluorine-doped silicon dioxide, silicon nitride, silicon oxynitride, or silicon carbide, etc.
- FIG. 2C fixed plugs 26 are formed in the sacrificial layer 24 and connected to the substrate 22 .
- the fixed plugs 26 can be formed by, for example, lithography, etching, deposition, and chemical mechanical polishing, which are well known by one skilled in this field and therefore the details are omitted.
- a fixed electrode 28 is formed on the sacrificial layer 24 and is connected to the substrate 22 via the fixed plugs 26 .
- the fixed electrode 28 includes, for example, metal or polysilicon; it acts as a bottom capacitor plate for sensing acoustic pressure in the MEMS acoustic pressure sensor device.
- another sacrificial layer 24 , metal plugs 30 and a metal layer 32 are formed on the fixed electrode 28 .
- another sacrificial layer 24 , other metal plugs 30 and another metal layer 32 are formed on the previously formed metal layer 32 , and as shown in FIG.
- a further other sacrificial layer 24 , further other metal plugs 30 and a further other metal layer 32 are formed on the previously formed metal layer 32 .
- supporting structure 34 and a top capacitor plate for sensing acoustic pressure in the MEMS acoustic pressure sensor device are formed.
- FIG. 2H shows that supporting structure 34 and a top capacitor plate for sensing acoustic pressure in the MEMS acoustic pressure sensor device.
- the top capacitor plate comprises multiple metal layers 32 and each metal layer includes multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered so that the top capacitor plate of the MEMS acoustic sensor device of the present invention forms a substantially blanket surface from top view, but the top capacitor plate includes openings at its lateral sides (that is, the metal plugs 30 in the top capacitor plate do not completely seal the lateral sides of the top capacitor plate), to allow vapor to pass through the openings of the top capacitor plate for etching the sacrificial layer 24 .
- the top capacitor plate is not limited to including only two metal layers shown in the figure, but may include more layers, which will be explained in more detail with reference to the examples shown in FIGS.
- substantially blanket surface from top view means that in a substantial area of the top capacitor plate, from top view, one can not see through the top capacitor plate from above its top layer to below its bottom layer.
- the multiple metal sections of each metal layer 32 and those of at least another metal layer 32 are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave when a multilayer structure 36 (shown in FIG. 2I ) receives acoustic pressure.
- the top capacitor plate As shown in FIG. 2I , after the top capacitor plate is formed, it is released to become the multilayer structure 36 by isotropic etch of the sacrificial layer 24 , so that the top capacitor plate is movable to sense acoustic pressure; a cavity 40 is also formed by the same process, wherein the isotropic etch includes, for example, reactive ion etch (RIE), plasma etch or HF vapor etch.
- RIE reactive ion etch
- the supporting structure 34 is fixed on the substrate 22 and connected with the multilayer structure 36 to support the multilayer structure 36 .
- the top capacitor plate includes the multilayer structure 36 which divides each metal layer into multiple sections; this prevents stress from accumulated in one large area.
- the multilayer structure 36 forms a substantially blanket surface from top view, so the acoustic pressure can adequately act on the top capacitor plate as a whole.
- the multilayer structure 36 is also advantageous with respect to manufacture, because the multilayer structure 36 includes openings at its lateral sides (the metal plugs 30 do not completely seal the lateral sides), which facilitate removing the sacrificial layer 24 by etch.
- the substrate 22 includes a top surface 221 and a bottom surface 222 as indicated by the thick dashed lines; from the bottom surface 222 , the substrate 22 can be partially removed to form an opening 42 , by inductively coupled plasma (ICP) or other anisotropic etch processes. Vents 44 are formed by lithography and etch from the opening 42 to the top surface 221 . The vents 44 connects the cavity 40 with the opening 42 for adjusting pressure inside the cavity 40 .
- ICP inductively coupled plasma
- FIG. 3 shows a second embodiment of the present invention, wherein the MEMS pressure sensor device of the present invention may further include an insulating layer 46 connected between the supporting structure 34 and the substrate 22 , and/or connected between the fixed plugs 26 and the substrate 22 .
- the insulating layer 46 can serve to insulate electrical connection or to act as an adhesion layer.
- FIG. 4 shows a third embodiment of the present invention.
- the supporting structure 34 in this embodiment may further include sacrificial layers 24 between the multiple metal layers 32 as shown in the figure.
- the sacrificial layers 24 can enhance the strength of the support structure 34 such that the MEMS acoustic pressure sensor device of the present invention has a better mechanical strength.
- FIGS. 5A-5J show a fourth embodiment of the present invention, which is an embodiment of the multilayer structure 36 , by top view and three-dimensional perspective view.
- FIG. 5A shows a top view of the bottom metal layer 52 of the top capacitor plate, and for convenience, let us assume that the metal layer 52 is the fourth metal layer in the manufacturing process.
- FIG. 5B shows the region 50 in FIG. 5A by three-dimensional perspective view.
- the fourth metal layer 52 includes multiple metal sections 521 which, for example, are arranged in parallel with one another and have gaps in between.
- multiple first metal plugs 531 are formed on the fourth metal layer 52 .
- a fifth metal layer 54 is formed on the multiple first metal plugs 531 .
- the fifth metal layer 54 includes multiple metal sections 541 which, for example, are arranged in parallel with one another and have gaps in between, and the multiple metal sections 541 of the fifth metal layer 54 and the multiple metal sections 521 of the fourth metal layer 52 are staggered.
- staggered means that the multiple metal sections 541 are not parallel to the multiple metal sections 521 , but overlap portions of the multiple metal sections 521 from top view.
- FIGS. 5G-5H from top view and three-dimensional perspective view, multiple second metal plugs 551 are formed on the fifth metal layer 54 .
- a sixth metal layer 56 is formed on the multiple second metal plugs 551 .
- the sixth metal layer 56 includes multiple metal sections 561 which, for example, are arranged in parallel with one another and have gaps in between, and the multiple metal sections 561 of the sixth metal layer 56 and the multiple metal sections 541 of the fifth metal layer 54 are staggered so that the multilayer structure 58 forms a substantially blanket surface from top view.
- FIGS. 6A-6D show a fifth embodiment of the present invention, which is another embodiment of the multilayer structure 36 , by top view and three-dimensional perspective view.
- the arrangement of the multiple metal sections in this embodiment is different from that in the fourth embodiment.
- FIG. 6A shows a seventh metal layer 62 and multiple third metal plugs 631 by top view
- FIG. 6B shows a three-dimensional perspective view of the region 60 shown in FIG. 6A .
- the serial number “seventh” is for distinguishing the present embodiment from the previous embodiment; it is not necessarily the seventh metal layer in the manufacturing process. So are the other serial numbers below.
- the seventh metal layer 62 includes multiple metal sections 621 which, for example, are arranged in parallel with one another and have gaps in between.
- an eighth metal layer 64 is formed on the multiple third metal plugs 631 .
- the eighth metal layer 64 includes multiple metal sections 641 which, for example, are arranged in parallel with one another and have gaps in between.
- the multiple metal sections 641 of the eighth metal layer 64 and the multiple metal sections 621 of the seventh metal layer 62 are staggered so that the multilayer structure 68 forms a substantially blanket surface from top view.
- FIGS. 7A-7F show a sixth embodiment of the present invention, which is another embodiment of the multilayer structure 36 , by top view and three-dimensional perspective view. Unlike the foregoing embodiments, the multilayer structure in this embodiment forms a almost totally blanket surface from top view.
- FIG. 7A shows a ninth metal layer 72 by top view while FIG. 7B shows a three-dimensional perspective view of the region 70 shown in FIG. 7A .
- the serial number “ninth” is for distinguishing the present embodiment from the previous embodiments; it is not necessarily the ninth metal layer in the manufacturing process. So are the other serial numbers below.
- the ninth metal layer 72 includes multiple metal sections 721 which, for example, are arranged in parallel with one another and have gaps in between.
- multiple fourth metal plugs 731 are formed on the ninth metal layer 72 .
- a tenth metal layer 74 are formed. on the multiple fourth metal plugs 731 .
- the tenth metal layer 74 includes multiple metal sections 741 which, for example, are very close to each other but have seams in between.
- the multiple metal sections 741 of the tenth metal layer 74 and the multiple metal sections 721 of the ninth metal layer 72 are staggered so that the seams between the multiple metal sections 741 do not totally overlap the gaps between the multiple metal sections 721 from top view.
- the tenth metal layer 74 overlaps a portion of the ninth metal layer 72 so that the multilayer structure 78 forms a substantially blanket surface from top view.
- each metal layer includes at least one material of gold, silver, titanium, tantalum, copper, aluminum, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
- each metal plug includes at least one material of tungsten, gold, silver, titanium, tantalum, copper, aluminum, tungsten carbide, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, tungsten oxide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tungsten nitride, tantalum nitride, copper nitride, or aluminum nitride.
- the present invention has been described in considerable detail with reference to certain preferred embodiments thereof. It should be understood that the description is for illustrative purpose, not for limiting the scope of the present invention. Those skilled in this art can readily conceive variations and modifications within the spirit of the present invention.
- the number of the metal layers in the present invention is not limited to the number shown in the embodiments, but can be any other number. As another example, it is not necessary for the staggered multiple metal sections to belong to two neighboring metal layers, but can belong to two metal layers with one or multiple metal layers between them as long as the multilayer structure forms a substantially blanket surface from top view.
- the number of the fixed plug or metal plug in each layer is not limited to one, but can be plural.
- each metal section, fixed plug or metal plug is not limited to a rectangle shape or a circle shape as shown in the figures, but also can be any other shape.
- other structures shown in the embodiments are not limited to the shapes as shown, but also can be any other shape.
- the present invention should cover all such and other modifications and variations, which should be interpreted to fall within the scope of the following claims and their equivalents.
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Abstract
The present invention discloses a Micro-Electro-Mechanical System (MEMS) acoustic pressure sensor device and a method for making same. The MEMS device includes: a substrate; a fixed electrode provided on the substrate; and a multilayer structure, which includes multiple metal layers and multiple metal plugs, wherein the multiple metal layers are connected by the multiple metal plugs. A cavity is formed between the multilayer structure and the fixed electrode. Each metal layer in the multilayer structure includes multiple metal sections. The multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave.
Description
- The present invention claims priority to TW 100109392, filed on Mar. 18, 2011.
- 1. Field of Invention
- The present invention relates to a Micro-Electro-Mechanical System (MEMS) acoustic pressure sensor device and its manufacturing method, in particular to such device that includes a multilayer structure having multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered, and a method for making such device.
- 2. Description of Related Art
-
FIG. 1 shows a multilayer MEMS structure disclosed in U.S. Pat. No. 7,202,101. As shown inFIG. 1 , themultilayer MEMS structure 10 is formed on a substrate 11 and it includes: asacrificial layer 12 formed on the substrate 11; afixed electrode 13; asacrificial layer 14; afirst metal layer 15 formed on thesacrificial layer 14; asacrificial layer 16; asecond metal layer 17 formed on thesacrificial layer 16; asacrificial layer 18; and a flexible ormovable diaphragm 19 formed by sealing each metal layer with a polymer film. - In this prior art, the
first metal layer 15 is a mesh-shaped metal layer to improve the properties of the MEMS acoustic pressure sensor device, wherein the mesh metal layer allows etching vapor to pass through the metal layers so that the etching vapor can react with and remove the desired portions of thesacrificial layers mesh metal layer 15 also alleviates the stress issue of the multilayer MEMS structure. - However, this mesh metal layer decreases the sensitivity of acoustic pressure and restricts the applications of the MEMS device. To counter, a part of the
sacrificial layers - For reference, U.S. Pat. No. 6,622,368, No. 7,049,051, No. 7,190,038 and No. 6,936,524 disclose other related MEMS acoustic pressure sensor devices.
- In the view of above, to overcome the drawback in the prior art, the present invention proposes a multilayer structure with staggered metal layers and its manufacturing method.
- An objective of the present invention is to provide a MEMS acoustic pressure sensor device.
- Another objective of the present invention is to provide a method for manufacturing a MEMS acoustic pressure sensor device.
- To achieve the foregoing objectives, in one perspective of the present invention, it provides a MEMS acoustic pressure sensor device comprising: a substrate; a fixed electrode provided on the substrate; and a multilayer structure including: multiple metal layers; and multiple metal plugs connecting the multiple metal layers; wherein a cavity is formed between the multilayer structure and the fixed electrode, and each metal layer in the multilayer structure includes multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave.
- In another perspective of the present invention, it provides a method for manufacturing a MEMS acoustic pressure sensor device, the method comprising: providing a substrate; forming a fixed electrode on the substrate; forming at least one sacrificial layer; forming multiple metal layers on the sacrificial layer, the multiple metal layers having multiple metal sections, respectively; and forming multiple metal plugs for connecting the multiple metal layers to form a multilayer structure, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave; and removing the sacrificial layer to form a cavity.
- The foregoing MEMS acoustic pressure sensor device preferably further comprises a supporting structure fixed on the substrate and connected with the multilayer structure for supporting the multilayer structure.
- The foregoing MEMS acoustic pressure sensor device preferably further comprises an insulating layer connected between the supporting structure and the substrate.
- In the foregoing MEMS acoustic pressure sensor device, each multiple metal layer preferably overlaps a portion of at least another metal layer from top view.
- In the foregoing MEMS acoustic pressure sensor device, the multilayer structure preferably includes at least one opening at a lateral side of the multilayer structure.
- In the foregoing MEMS acoustic pressure sensor device, the substrate preferably includes at least one vent.
- In the foregoing MEMS acoustic pressure sensor device, each metal layer preferably includes at least one material of gold, silver, titanium, tantalum, copper, aluminum, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
- In the foregoing MEMS acoustic pressure sensor device, each metal plug preferably includes at least one material of tungsten, gold, silver, titanium, tantalum, copper, aluminum, tungsten carbide, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, tungsten oxide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, tungsten nitride, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
- The objectives, technical details, features, and effects of the present invention will be better understood with regard to the detailed description of the embodiments below, with reference to the drawings.
-
FIG. 1 shows a multilayer MEMS structure disclosed in U.S. Pat. No. 7,202,101. -
FIGS. 2A-2J illustrate, by cross-section view, a manufacturing process according to a first embodiment of the present invention. -
FIG. 3 shows a second embodiment of the present invention. -
FIG. 4 shows a third embodiment of the present invention. -
FIGS. 5A-5J show a fourth embodiment of the present invention. -
FIGS. 6A-6D show a fifth embodiment of the present invention. -
FIGS. 7A-7F show a sixth embodiment of the present invention. - The drawings as referred to throughout the description of the present invention are for illustration only, to show the interrelations between the layers and the process steps, but not drawn according to actual scale.
-
FIGS. 2A-2J illustrate, by cross-section view, a manufacturing process according to a first embodiment of the present invention. As shown inFIG. 2A , asubstrate 22 is provided, and thesubstrate 22 may be, for example but not limited to, a silicon substrate. As shown inFIG. 2B , asacrificial layer 24 is formed on thesubstrate 22, which may include, for example but not limited to, a dielectric material of silicon dioxide, fluorine-doped silicon dioxide, silicon nitride, silicon oxynitride, or silicon carbide, etc. As shown inFIG. 2C ,fixed plugs 26 are formed in thesacrificial layer 24 and connected to thesubstrate 22. Thefixed plugs 26 can be formed by, for example, lithography, etching, deposition, and chemical mechanical polishing, which are well known by one skilled in this field and therefore the details are omitted. - As shown in
FIG. 2D , afixed electrode 28 is formed on thesacrificial layer 24 and is connected to thesubstrate 22 via thefixed plugs 26. Thefixed electrode 28 includes, for example, metal or polysilicon; it acts as a bottom capacitor plate for sensing acoustic pressure in the MEMS acoustic pressure sensor device. As shown inFIG. 2E , anothersacrificial layer 24,metal plugs 30 and ametal layer 32 are formed on thefixed electrode 28. As shown inFIGS. 2F and 2G , anothersacrificial layer 24, other metal plugs 30 and anothermetal layer 32 are formed on the previously formedmetal layer 32, and as shown inFIG. 2H , a further othersacrificial layer 24, further other metal plugs 30 and a furtherother metal layer 32 are formed on the previously formedmetal layer 32. As shown inFIG. 2H , supportingstructure 34 and a top capacitor plate for sensing acoustic pressure in the MEMS acoustic pressure sensor device are formed. In addition,FIG. 2H also shows that the top capacitor plate comprisesmultiple metal layers 32 and each metal layer includes multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered so that the top capacitor plate of the MEMS acoustic sensor device of the present invention forms a substantially blanket surface from top view, but the top capacitor plate includes openings at its lateral sides (that is, the metal plugs 30 in the top capacitor plate do not completely seal the lateral sides of the top capacitor plate), to allow vapor to pass through the openings of the top capacitor plate for etching thesacrificial layer 24. The top capacitor plate is not limited to including only two metal layers shown in the figure, but may include more layers, which will be explained in more detail with reference to the examples shown inFIGS. 5A-5J , 6A-6D and 7A-7F. Furthermore, the wording “substantially blanket surface from top view” means that in a substantial area of the top capacitor plate, from top view, one can not see through the top capacitor plate from above its top layer to below its bottom layer. In other words, the multiple metal sections of eachmetal layer 32 and those of at least anothermetal layer 32 are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave when a multilayer structure 36 (shown inFIG. 2I ) receives acoustic pressure. - As shown in
FIG. 2I , after the top capacitor plate is formed, it is released to become themultilayer structure 36 by isotropic etch of thesacrificial layer 24, so that the top capacitor plate is movable to sense acoustic pressure; acavity 40 is also formed by the same process, wherein the isotropic etch includes, for example, reactive ion etch (RIE), plasma etch or HF vapor etch. Further, as shown in the figure, the supportingstructure 34 is fixed on thesubstrate 22 and connected with themultilayer structure 36 to support themultilayer structure 36. - According to the present invention, the top capacitor plate includes the
multilayer structure 36 which divides each metal layer into multiple sections; this prevents stress from accumulated in one large area. Although the top capacitor plate is divided into multiple small sections in each layer, themultilayer structure 36 forms a substantially blanket surface from top view, so the acoustic pressure can adequately act on the top capacitor plate as a whole. Themultilayer structure 36 is also advantageous with respect to manufacture, because themultilayer structure 36 includes openings at its lateral sides (the metal plugs 30 do not completely seal the lateral sides), which facilitate removing thesacrificial layer 24 by etch. - Referring to the cross-section view of
FIG. 2J , thesubstrate 22 includes atop surface 221 and abottom surface 222 as indicated by the thick dashed lines; from thebottom surface 222, thesubstrate 22 can be partially removed to form anopening 42, by inductively coupled plasma (ICP) or other anisotropic etch processes.Vents 44 are formed by lithography and etch from theopening 42 to thetop surface 221. Thevents 44 connects thecavity 40 with theopening 42 for adjusting pressure inside thecavity 40. -
FIG. 3 shows a second embodiment of the present invention, wherein the MEMS pressure sensor device of the present invention may further include an insulatinglayer 46 connected between the supportingstructure 34 and thesubstrate 22, and/or connected between the fixed plugs 26 and thesubstrate 22. The insulatinglayer 46 can serve to insulate electrical connection or to act as an adhesion layer. -
FIG. 4 shows a third embodiment of the present invention. Different from the first embodiment, the supportingstructure 34 in this embodiment may further includesacrificial layers 24 between themultiple metal layers 32 as shown in the figure. Thesacrificial layers 24 can enhance the strength of thesupport structure 34 such that the MEMS acoustic pressure sensor device of the present invention has a better mechanical strength. -
FIGS. 5A-5J show a fourth embodiment of the present invention, which is an embodiment of themultilayer structure 36, by top view and three-dimensional perspective view.FIG. 5A shows a top view of thebottom metal layer 52 of the top capacitor plate, and for convenience, let us assume that themetal layer 52 is the fourth metal layer in the manufacturing process.FIG. 5B shows theregion 50 inFIG. 5A by three-dimensional perspective view. As shown inFIGS. 5A-5B , thefourth metal layer 52 includesmultiple metal sections 521 which, for example, are arranged in parallel with one another and have gaps in between. - Referring to
FIGS. 5C-5D , from top view and three-dimensional perspective view, multiple first metal plugs 531 are formed on thefourth metal layer 52. Referring toFIGS. 5E-5F , from top view and three-dimensional perspective view, afifth metal layer 54 is formed on the multiple first metal plugs 531. As shown inFIGS. 5E-5F , thefifth metal layer 54 includesmultiple metal sections 541 which, for example, are arranged in parallel with one another and have gaps in between, and themultiple metal sections 541 of thefifth metal layer 54 and themultiple metal sections 521 of thefourth metal layer 52 are staggered. The word “staggered” means that themultiple metal sections 541 are not parallel to themultiple metal sections 521, but overlap portions of themultiple metal sections 521 from top view. - Referring to
FIGS. 5G-5H , from top view and three-dimensional perspective view, multiple second metal plugs 551 are formed on thefifth metal layer 54. Referring toFIGS. 5I-5J , from top view and three-dimensional perspective view, asixth metal layer 56 is formed on the multiple second metal plugs 551. As shown inFIGS. 5I-5J , thesixth metal layer 56 includesmultiple metal sections 561 which, for example, are arranged in parallel with one another and have gaps in between, and themultiple metal sections 561 of thesixth metal layer 56 and themultiple metal sections 541 of thefifth metal layer 54 are staggered so that themultilayer structure 58 forms a substantially blanket surface from top view. -
FIGS. 6A-6D show a fifth embodiment of the present invention, which is another embodiment of themultilayer structure 36, by top view and three-dimensional perspective view. The arrangement of the multiple metal sections in this embodiment is different from that in the fourth embodiment.FIG. 6A shows aseventh metal layer 62 and multiple third metal plugs 631 by top view, andFIG. 6B shows a three-dimensional perspective view of theregion 60 shown inFIG. 6A . (The serial number “seventh” is for distinguishing the present embodiment from the previous embodiment; it is not necessarily the seventh metal layer in the manufacturing process. So are the other serial numbers below.) As shown inFIGS. 6A-6B , theseventh metal layer 62 includesmultiple metal sections 621 which, for example, are arranged in parallel with one another and have gaps in between. - Referring to
FIGS. 6C-6D , from top view and three-dimensional perspective view, aneighth metal layer 64 is formed on the multiple third metal plugs 631. As shown inFIGS. 6C-6D , theeighth metal layer 64 includesmultiple metal sections 641 which, for example, are arranged in parallel with one another and have gaps in between. Similarly, themultiple metal sections 641 of theeighth metal layer 64 and themultiple metal sections 621 of theseventh metal layer 62 are staggered so that themultilayer structure 68 forms a substantially blanket surface from top view. -
FIGS. 7A-7F show a sixth embodiment of the present invention, which is another embodiment of themultilayer structure 36, by top view and three-dimensional perspective view. Unlike the foregoing embodiments, the multilayer structure in this embodiment forms a almost totally blanket surface from top view.FIG. 7A shows a ninth metal layer 72 by top view whileFIG. 7B shows a three-dimensional perspective view of theregion 70 shown inFIG. 7A . (The serial number “ninth” is for distinguishing the present embodiment from the previous embodiments; it is not necessarily the ninth metal layer in the manufacturing process. So are the other serial numbers below.) As shown inFIGS. 7A-7B , the ninth metal layer 72 includesmultiple metal sections 721 which, for example, are arranged in parallel with one another and have gaps in between. - Referring to
FIGS. 7C-7D , from top view and three-dimensional perspective view, multiple fourth metal plugs 731 are formed on the ninth metal layer 72. Referring toFIGS. 7E-7F , from top view and three-dimensional perspective view, atenth metal layer 74 are formed. on the multiple fourth metal plugs 731. As shown inFIGS. 7E-7F , thetenth metal layer 74 includesmultiple metal sections 741 which, for example, are very close to each other but have seams in between. Further, themultiple metal sections 741 of thetenth metal layer 74 and themultiple metal sections 721 of the ninth metal layer 72 are staggered so that the seams between themultiple metal sections 741 do not totally overlap the gaps between themultiple metal sections 721 from top view. Thetenth metal layer 74 overlaps a portion of the ninth metal layer 72 so that themultilayer structure 78 forms a substantially blanket surface from top view. - In the foregoing embodiments, preferably, each metal layer includes at least one material of gold, silver, titanium, tantalum, copper, aluminum, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride. Preferably, each metal plug includes at least one material of tungsten, gold, silver, titanium, tantalum, copper, aluminum, tungsten carbide, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, tungsten oxide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tungsten nitride, tantalum nitride, copper nitride, or aluminum nitride.
- The present invention has been described in considerable detail with reference to certain preferred embodiments thereof. It should be understood that the description is for illustrative purpose, not for limiting the scope of the present invention. Those skilled in this art can readily conceive variations and modifications within the spirit of the present invention. For example, the number of the metal layers in the present invention is not limited to the number shown in the embodiments, but can be any other number. As another example, it is not necessary for the staggered multiple metal sections to belong to two neighboring metal layers, but can belong to two metal layers with one or multiple metal layers between them as long as the multilayer structure forms a substantially blanket surface from top view. As another example, the number of the fixed plug or metal plug in each layer is not limited to one, but can be plural. As another example, from top view, each metal section, fixed plug or metal plug is not limited to a rectangle shape or a circle shape as shown in the figures, but also can be any other shape. Likely, other structures shown in the embodiments are not limited to the shapes as shown, but also can be any other shape. Thus, the present invention should cover all such and other modifications and variations, which should be interpreted to fall within the scope of the following claims and their equivalents.
Claims (15)
1. A MEMS acoustic pressure sensor device, comprising:
a substrate;
a fixed electrode provided on the substrate; and
a multilayer structure including:
multiple metal layers; and
multiple metal plugs connecting the multiple metal layers;
wherein a cavity is formed between the multilayer structure and the fixed electrode, and each metal layer in the multilayer structure includes multiple metal sections, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave.
2. The MEMS acoustic pressure sensor device of claim 1 , further comprising a supporting structure fixed on the substrate and connected with the multilayer structure for supporting the multilayer structure.
3. The MEMS acoustic pressure sensor device of claim 2 , further comprising an insulating layer connected between the supporting structure and the substrate.
4. The MEMS acoustic pressure sensor device of claim 1 , wherein each multiple metal layer overlaps a portion of at least another metal layer from top view.
5. The MEMS acoustic pressure sensor device of claim 1 , wherein the multilayer structure includes at least one opening at a lateral side of the multilayer structure.
6. The MEMS acoustic pressure sensor device of claim 1 , wherein the substrate includes at least one vent.
7. The MEMS acoustic pressure sensor device of claim 1 , wherein each metal layer includes at least one material of gold, silver, titanium, tantalum, copper, aluminum, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
8. The MEMS acoustic pressure sensor device of claim 1 , wherein each metal plug includes at least one material of tungsten, gold, silver, titanium, tantalum, copper, aluminum, tungsten carbide, titanium carbide, tantalum carbide, copper carbide, aluminum carbide, tungsten oxide, titanium oxide, tantalum oxide, copper oxide, aluminum oxide, tungsten nitride, titanium nitride, tantalum nitride, copper nitride, or aluminum nitride.
9. A method for manufacturing a MEMS acoustic pressure sensor device, comprising:
providing a substrate;
forming a fixed electrode on the substrate;
forming at least one sacrificial layer;
forming multiple metal layers on the sacrificial layer, the multiple metal layers having multiple metal sections, respectively; and
forming multiple metal plugs for connecting the multiple metal layers to form a multilayer structure, wherein the multiple metal sections of one metal layer and those of at least another metal layer are staggered to form a substantially blanket surface as viewed from a moving direction of an acoustic wave; and
removing the sacrificial layer to form a cavity.
10. The method of claim 9 , further comprising forming a supporting structure fixed on the substrate and connected with the multilayer structure for supporting the multilayer structure.
11. The method of claim 10 , further comprising forming an insulating layer connected between the supporting structure and the substrate.
12. The method of claim 9 , wherein each multiple metal layer overlaps a portion of at least another metal layer form top view.
13. The method of claim 9 , wherein the multilayer structure includes at least one opening at a lateral side of the multilayer structure.
14. The method of claim 9 , wherein the step of removing the sacrificial layer includes etching the sacrificial layer by reactive ion etching (RIE), plasma etching, or HF vapor etching.
15. The method of claim 9 , further comprising forming at least one vent in the substrate.
Priority Applications (2)
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US15/494,535 US10081538B2 (en) | 2011-03-18 | 2017-04-23 | MEMS acoustic pressure sensor device and method for making same |
US16/100,447 US11053116B2 (en) | 2011-03-18 | 2018-08-10 | MEMS acoustic pressure sensor device and method for making same |
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TW100109392A TWI430424B (en) | 2011-03-18 | 2011-03-18 | Mems acoustic pressure sensor device and method for making same |
TW100109392 | 2011-03-18 |
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US15/494,535 Continuation US10081538B2 (en) | 2011-03-18 | 2017-04-23 | MEMS acoustic pressure sensor device and method for making same |
US15/494,535 Continuation-In-Part US10081538B2 (en) | 2011-03-18 | 2017-04-23 | MEMS acoustic pressure sensor device and method for making same |
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US13/068,554 Abandoned US20120235255A1 (en) | 2011-03-18 | 2011-05-14 | MEMS acoustic pressure sensor device and method for making same |
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CN114674485A (en) * | 2022-02-21 | 2022-06-28 | 华中科技大学 | Small-range MEMS capacitive pressure sensor and preparation method thereof |
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DE10160830A1 (en) * | 2001-12-11 | 2003-06-26 | Infineon Technologies Ag | Micromechanical sensor comprises a counter element lying opposite a moving membrane over a hollow chamber and containing openings which are formed by slits |
US7049051B2 (en) * | 2003-01-23 | 2006-05-23 | Akustica, Inc. | Process for forming and acoustically connecting structures on a substrate |
US20050095814A1 (en) * | 2003-11-05 | 2005-05-05 | Xu Zhu | Ultrathin form factor MEMS microphones and microspeakers |
EP1908727A1 (en) * | 2006-10-03 | 2008-04-09 | Seiko Epson Corporation | Wafer-level MEMS package and manufacturing method thereof |
JP2009238905A (en) * | 2008-03-26 | 2009-10-15 | Nippon Telegr & Teleph Corp <Ntt> | Mounting structure and mounting method for semiconductor element |
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- 2011-03-18 TW TW100109392A patent/TWI430424B/en not_active IP Right Cessation
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US20050000932A1 (en) * | 2003-01-23 | 2005-01-06 | Gabriel Kaigham J. | Multi-metal layer MEMS structure and process for making the same |
US20100230767A1 (en) * | 2009-03-12 | 2010-09-16 | Seiko Epson Corporation | Mems sensor, mems sensor manufacturing method, and electronic device |
US20120167683A1 (en) * | 2010-12-30 | 2012-07-05 | Pixart Imaging Incorporation | MEMS device and deformation protection structure therefor and method for making same |
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US20150102701A1 (en) * | 2013-10-11 | 2015-04-16 | Pixart Imaging Incorporation | Micro-electro-mechanical system device with enhanced structural strength |
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CN114674485A (en) * | 2022-02-21 | 2022-06-28 | 华中科技大学 | Small-range MEMS capacitive pressure sensor and preparation method thereof |
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JP2012199917A (en) | 2012-10-18 |
TWI430424B (en) | 2014-03-11 |
JP5330558B2 (en) | 2013-10-30 |
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